Which instruments are mose closely related recorder and harmonium or accordion and conconccen?

The recorder is more closely related to the harmonium than to the Accordion and concertina. Both the recorder and harmonium are woodwind and keyboard instruments, respectively, while the accordion and concertina are free-reed instruments. The recorder produces sound through an air column, while the harmonium uses a keyboard to activate reeds, creating a different sound production mechanism. In contrast, the accordion and concertina rely on bellows and free reeds but do not share the same woodwind characteristics as the recorder.